U.S. patent number 5,558,596 [Application Number 08/328,535] was granted by the patent office on 1996-09-24 for method and system using fuzzy logic for controlling a cvt transmission.
This patent grant is currently assigned to Hitachi Automotive Engineering Company, Hitachi, Ltd.. Invention is credited to Masao Adachi, Minoru Ohkubo, Kazuhiko Sato, Makoto Shioya.
United States Patent |
5,558,596 |
Adachi , et al. |
September 24, 1996 |
Method and system using fuzzy logic for controlling a CVT
transmission
Abstract
According to the present invention, the driver's operation
quantity and the vehicle running status are measured, the target
value of speed ratio or the target value of revolution speed on the
input side of the transmission is determined on the basis of the
above measured values, and the speed ratio is changed using
different algorithms (particularly fuzzy rules) on the basis of the
magnitude of deviation between the target value and the actual
value. Furthermore, when a vehicle has a continuously variable
transmission, a change of at least one of the vehicle acceleration
and the shaft torque of a drive wheel is predicted, the engine
output torque is controlled on the basis of the prediction, and
finite speed ratio characteristics or intermediate characteristics
between finite speed ratio characteristics and continuously
variable speed ratio characteristics are controlled for the
continuously variable transmission. By doing this, speed ratio
control stressed on stability is available when the absolute value
of the above deviation is small, while speed ratio control stressed
on rapid response and smooth acceleration variation is available
when the absolute value of the deviation is large. Furthermore, a
smooth acceleration feeling and a rapid acceleration response can
be realized, the maneuverability is improved, and the driver can
find pleasure in more speed ratio characteristics.
Inventors: |
Adachi; Masao (Zama,
JP), Shioya; Makoto (Suginami-ku, JP),
Sato; Kazuhiko (Katsuta, JP), Ohkubo; Minoru
(Katsuta, JP) |
Assignee: |
Hitachi, Ltd. (Tokyo,
JP)
Hitachi Automotive Engineering Company (Ibaraki-ken,
JP)
|
Family
ID: |
18018070 |
Appl.
No.: |
08/328,535 |
Filed: |
October 25, 1994 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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794038 |
Nov 19, 1991 |
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Foreign Application Priority Data
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Nov 19, 1990 [JP] |
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2-311507 |
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Current U.S.
Class: |
701/57; 477/48;
477/46 |
Current CPC
Class: |
F16H
61/66259 (20130101); B60W 2050/0057 (20130101); F16H
2061/0081 (20130101); F16H 59/48 (20130101); F16H
59/40 (20130101); F16H 59/36 (20130101); F16H
59/42 (20130101); F16H 59/24 (20130101) |
Current International
Class: |
F16H
61/66 (20060101); F16H 61/662 (20060101); F16H
59/38 (20060101); F16H 59/36 (20060101); F16H
59/40 (20060101); F16H 59/48 (20060101); F16H
59/24 (20060101); F16H 59/42 (20060101); F16H
61/00 (20060101); B60K 041/12 () |
Field of
Search: |
;477/45,46,48,49
;364/424.1 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
Prototype Design and Testing of the Half Toroidal CVT, Hisashi
Machida and Nobuhide Kurachi, Trilogy R&D, Nippon Seiko K. K.,
SAE 900552 (1990). .
"Electronically Controlled Continuously Variable Transmission
(ECVT-II)", International Congress on Transporation Electronics
Proceedings, Y. Kasai, Y. Morimoto, Oct. 17-18, 1988, pp.
33-42..
|
Primary Examiner: Ta; Khoi Q.
Attorney, Agent or Firm: Antonelli, Terry, Stout &
Kraus
Parent Case Text
This application is a continuation of Ser. No. 07/794,038, filed
Nov. 19, 1991, now abandoned.
Claims
What is claimed is:
1. In a vehicle transmission system including an operation sensor,
a running status sensor, a processor and a memory storing relation
data between target speed and data measured by use of said
operation sensor and said running status sensor, a speed ratio
control method for a continuously variable transmission which
transfer inputs from a power source to a drive wheel, comprising
the steps of;
measuring through said operation and said running status sensors, a
driver's operation quantity and a vehicle running status;
determining through said processor, by use of said relation data,
one of a target value of speed ratio and a target value of
revolution speed on an input of said transmission on a basis of
results of said measuring step; and
changing a speed ratio using at least two different algorithms in
correspondence with whether or not a value of deviation between
said target value and a current actual value is greater than a
threshold value.
2. A speed ratio control method for a transmission according to
claim 1, wherein a changing in said changing step is performed on a
deviation and velocity of deviation variation when an absolute
value of said deviation is smaller than a predetermined value.
3. In a vehicle transmission system including an operation sensor,
a running status sensor, a processor and a memory storing relation
data between target speed and data measured by use of said
operation sensor and said running status sensor, a speed ratio
control method for a continuously variable transmission which
transfer inputs from a power source to a drive wheel, comprising
the steps of;
measuring through said operation and said running status sensors, a
driver's operation quantity and a vehicle running status;
determining through said processor, by use of said relation data,
one of a target value of speed ratio and a target value of
revolution speed on an input of said transmission on a basis of
results of said measuring step; and
changing a speed ratio using at least two different algorithms in
correspondence with whether or not a value of deviation between
said target value and a current actual value is greater than a
threshold value;
wherein at least one of said different algorithms uses fuzzy logic
rules.
4. In a vehicle transmission system including an operation sensor,
a running status sensor, a processor and a memory storing relation
data between target speed and data measured by use of said
operation sensor and said running status sensor, a speed ratio
control method for a continuously variable transmission which
transfer inputs from a power source to a drive wheel, comprising
the steps of;
measuring through said operation and said running status sensors, a
driver's operation quantity and a vehicle running status;
determining through said processor, by use of said relation data,
one of a target value of speed ratio and a target value of
revolution speed on an input of said transmission on a basis of
results of said measuring step; and
changing a speed ratio using at least two different algorithms in
correspondence with whether or not a value of deviation between
said target value and a current actual value is greater than a
threshold value;
wherein said changing step is performed according to when an
absolute value of said deviation is larger than a predetermined
value, said speed ratio is changed based on an at least one of a
vehicle acceleration value, and a value which is at least one of a
ratio and difference between a predicted time until said deviation
becomes 0, and a predicted response time necessary for stopping a
speed by use of a speed ratio control actuator.
5. In a vehicle transmission system including an operation sensor,
a running status sensor, a processor and a memory storing relation
data between target speed and data measured by use of said
operation sensor and said running status sensor, a speed ratio
control method for a continuously variable transmission which
transfer inputs from a power source to a drive wheel, comprising
the steps of;
measuring through said operation and said running status sensors, a
driver's operation quantity and a vehicle running status;
determining through said processor, by use of said relation data,
one of a target value of speed ratio and a target value of
revolution speed on an input of said transmission on a basis of
results of said measuring step; and
changing a speed ratio using at least two different algorithms in
correspondence with whether or not a value of deviation between
said target value and a current actual value is greater than a
threshold value;
wherein said changing step further comprises: when both an
acceleration pedal position variation velocity and an absolute
value of said deviation between said target value and the actual
value are smaller than predetermined values, said speed ratio is
not changed.
6. In a vehicle including an operation sensor, a running status
sensor, a processing means and a memory storing relation data
between target speed and data measured by use of said operation
sensor and said running status sensor, a speed ratio control system
of a continuously variable transmission which transfers inputs from
a power source to a drive wheel, comprising:
means for measuring a driver's operation quantity and a vehicle
running status;
means for determining one of a target value of speed ratio and a
target value of revolution speed on an input of said transmission
on a basis of results from said means for measuring; and
means for changing a speed ratio using at least two different
algorithms in correspondence with whether or not a value of
deviation between said target value and a current actual value is
greater than a threshold value.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method and system for
controlling a vehicle transmission for realizing smoothing of
acceleration and deceleration and efficiently using the power
source energy, thereby realizing desired feeling of acceleration
and deceleration.
2. Description of the Prior Art
The conventional speed ratio control method of a transmission is
described in International Congress On Transportation Electronics
Processings (1988), pp 33 to 42 (hereinafter referred to as Prior
Art 1). In the present invention, the target speed ratio is
determined from the real speed ratio, engine throttle opening, and
vehicle velocity, and the speed ratio variation velocity is
determined from the following expression: ##EQU1## and the speed
ratio is controlled so that the real speed ratio variation velocity
matches this speed ratio variation velocity. The factor 1 of the
above expression is changed by fuzzy logic rules depending on the
vehicle velocity and engine throttle opening. The factor 2 is
changed by fuzzy logic rules depending on the "target speed
ratio--real speed ratio" and target speed ratio variation velocity.
Changing the speed ratio characteristics of a continuously variable
transmission is described in Japanese Patent Application Laid-Open
No. 1988-269744 (hereinafter referred to as Prior Art 2).
In the above Prior Art 1, the user can set desirable speed ratio
characteristics by inputting of the relational curve between
vehicle velocity and engine speed, and selecting one of "fast",
"medium", and "slow" of the speed ratio variation velocity.
In the above Prior Arts 1 and 2, synchronization between the time
that the deviation becomes 0 and the time that the speed ratio
control actuator stops speed ratio change, use of vehicle
acceleration information, and engine control are not considered,
and there are problems imposed such as unsmooth changes of
acceleration and overshoot of engine speed. The easiness of
maneuverability is not considered, and there is a problem imposed
such that when the throttle opening is changed, the speed ratio is
changed always and the engine speed changes widely.
SUMMARY OF THE INVENTION
The first object of the present invention is to provide a speed
ratio control method and system for realizing smooth acceleration
variations and preventing wasting of energy of the power source due
to engine speed overshoot or large variations of the input side
revolution speed of a transmission.
The second object of the present invention is to provide a control
method and system for realizing smooth acceleration variations and
rapid acceleration and deceleration response by engine control.
In the above Prior Art 2, the easiness of maneuverability is not
considered, and hence there is a problem imposed such that when
changing a vehicle with a finite speed automatic transmission to a
vehicle with a continuously variable transmission, a feeling of
uneasiness occurs in the riding comfort. Furthermore, a means for
continuously changing the speed ratio variation velocity is not
considered, and hence there is a problem imposed such that the
transient speed ratio characteristics cannot be changed as
desired.
The third object of the present invention is to provide a speed
ratio control method and system for minimizing the above feeling of
uneasiness in the riding comfort due to vehicle changing and a
speed ratio control method and system for finding pleasure in more
speed ratio characteristics.
The fourth object of the present invention is to provide a speed
ratio control method and system for changing the speed ratio
variation velocity characteristics continuously as desired by an
instruction of the driver.
In the above prior arts, changes of the vehicle response
characteristics due to changes of the running resistance such as
the number of passengers and road gradient and output reduction of
the engine caused by atmospheric pressure changes are not
considered, and the speed ratio is always controlled by a constant
control parameter. Therefore, there is a problem imposed such that
a sufficient acceleration feeling cannot be obtained for a rapid
acceleration response cannot be obtained.
The fifth object of the present invention is to provide a speed
ratio control method and system for a continuously variable
transmission for providing no feeling of a reduction of the
acceleration force for the same vehicle velocity and throttle
opening under the conditions that the above vehicle response
characteristics are changed.
The sixth object of the present invention is to provide a speed
ratio control method and system for a continuously variable
transmission wherein the acceleration and deceleration response
satisfies the contrary conditions of shortening of the response
time and prevention of down-shock (negative derivative of
acceleration force generated during acceleration) and is smooth and
quick.
The seventh object of the present invention is to provide a speed
ratio control method and system for a continuously variable
transmission by calculating variations of the target acceleration
response or speed ratio control parameter for being adaptive finely
to various vehicle velocities and throttle openings or changes of
the vehicle response characteristics.
So as to accomplish the above objects, the present invention
changes the speed ratio according to different algorithms (for
example, different fuzzy rules) on the basis of the magnitude of
the deviation between the target value and the real value. So as to
provide smooth acceleration changes, when the absolute value of the
deviation is large the present invention changes the speed ratio on
the basis of at least one of the ratio between the predicting time
until the deviation becomes 0 and the predicting response time
necessary for stopping the speed ratio change by the speed ratio
control actuator, the difference thereof, and the vehicle
derivative of acceleration.
Furthermore, so as to prevent wasting of energy of the power source
and maintain the stability of the transmission system, the present
invention changes the speed ratio on the basis of the deviation and
deviation variation velocity when the absolute value of the
deviation is small and inhibits to change the speed ratio when both
the deviation and the acceleration pedal position variation
velocity are small.
Next, a structure (second structure) which is a modification of the
above mentioned structure of the present invention for realizing
both smooth acceleration variation and acceleration and
deceleration rapid response mentioned above controls the engine
output torque by providing processing for predicting a change of at
least one of the vehicle acceleration and the axial torque of the
drive wheel. Furthermore, the structure uses fuzzy logic for
control of the engine output on the basis of the variation
prediction processing. The variation prediction processing uses
information of the speed ratio, transmission input side revolution
speed and engine revolution speed, or information of throttle
opening, and vehicle derivative of acceleration.
The third structure of the present invention, which is suitable for
minimizing the above feeling of uneasiness due to vehicle changing,
provides processing for setting or selecting speed ratio
characteristics of a finite speed automatic transmission in a
continuously variable transmission so as to improve the easiness of
maneuverability of a vehicle with a continuously variable
transmission and to find pleasure in more speed ratio
characteristics.
Furthermore, the structure provides processing for setting or
selecting any speed ratio characteristics continuously between the
finite speed ratio characteristics and the continuously variable
speed ratio characteristics.
The fourth structure of the present invention, which is suitable
for providing the above transient speed ratio characteristics
according to the user's desire, provides processing for correcting
the speed ratio velocity using prediction information necessary for
reaching the target speed ratio on the basis of the user's
instruction.
The fifth structure of the present invention, which is suitable for
the object of providing no feeling of a reduction of the
acceleration force for the same vehicle velocity and throttle
opening, provides processing for calculating the target
acceleration response in accordance with the vehicle velocity and
throttle opening, processing for comparing the calculated target
acceleration response with the measured acceleration response, and
processing for changing the speed ratio control parameter on the
basis of the comparison result information.
A structure (sixth structure) of the present invention, which is
suitable for accomplishing the above sixth object, performs the
comparison processing using the index value of the acceleration
response time and the index value of the acceleration down-shock
magnitude.
The seventh structure of the present invention, which is suitable
for accomplishing the above seventh object, uses fuzzy logic for at
least one of calculation of the target acceleration response and
changing of the speed ratio control parameter.
According to the above structures of the present invention, the
speed ratio is changed by different fuzzy rules or algorithms on
the basis of the magnitude of the deviation. Therefore, speed ratio
control which stresses stability is available when the absolute
value of the deviation is small, while speed ratio control which
attaches importance to a rapid response and smooth acceleration
variation is available when the absolute value of the deviation is
large. By doing this, smooth acceleration variation is realized,
and the speed ratio and engine revolution speed are prevented from
overshooting.
Especially when the absolute value of the deviation is large, the
speed ratio is changed by the fuzzy logic rules on the basis of the
ratio or difference between the predicting time until the deviation
becomes 0 and the predicting response time necessary for stopping
the speed ratio change by the speed ratio control actuator.
Therefore, sudden changes of the acceleration due to excessive
speed ratio variations or overshooting of the speed ratio can be
prevented and the acceleration is changed smoothly. When the
absolute value of the deviation is large, the speed ratio is
changed by the fuzzy logic rules on the basis of the derivative of
acceleration. Therefore, a decrease in the acceleration during
acceleration or an increase in the acceleration during deceleration
can be prevented and the acceleration is changed smoothly. When the
absolute value of the deviation is small, the speed ratio is
changed by the fuzzy logic rules on the basis of the deviation and
deviation variation velocity. Therefore, the speed ratio is
prevented from overshooting, wasteful variations of the revolution
speed on the power source side are eliminated, and wasting of
energy can be prevented.
When the deviation and the acceleration pedal position variation
velocity are small, changing the speed ratio is inhibited.
Therefore, excessive speed ratio variations and frequent variations
of the revolution speed on the power source side can be prevented,
and wasting of energy of the power source can be prevented.
According to the second structure of the present invention, the
engine output torque can be controlled so as to compensate for
changes of the acceleration during acceleration or deceleration on
the basis of the processing for predicting changes of at least one
of the vehicle acceleration and the axial torque of the drive
wheel. Therefore, a smooth acceleration feeling and a rapid
response to acceleration or deceleration can be realized.
Furthermore, changes of at least one of the vehicle acceleration
and the axial torque of the drive wheel can be predicted from the
speed ratio, primary pulley revolution speed (revolution speed on
the transmission input side), engine revolution speed, throttle
opening, or vehicle derivative of acceleration information.
Therefore, a smooth acceleration feeling and a rapid acceleration
response can be realized.
At least one of the prediction and the torque control is performed
by fuzzy logic rules. Therefore, a smooth acceleration feeling and
a rapid acceleration response can be realized.
According to the third structure of the present invention, the
processing that the speed ratio characteristics of a finite speed
automatic transmission are set or selected in a continuously
variable transmission is provided. Therefore, the user can enjoy
finite speed ratio characteristics and can find pleasure in more
speed ratio characteristics because the easiness of maneuverability
is improved.
Furthermore, by the processing that speed ratio characteristics are
set or selected continuously, finite speed ratio characteristics
can be slowly changed to continuously variable speed ratio
characteristics. Therefore, the easiness of maneuverability is
improved and the user can find pleasure in more speed ratio
characteristics.
According to the fourth structure of the present invention, the
processing that the speed ratio velocity can be corrected by using
the predicting time necessary for reaching the target speed ratio
on the basis of the user's input instruction is provided.
Therefore, the speed ratio variation velocity characteristics can
be changed continuously and the acceleration feeling which is to
the user's taste can be easily set.
According to the fifth structure of the present invention, the best
vehicle acceleration response corresponding to the vehicle velocity
and throttle opening is calculated as a target acceleration
response, and the self adjustment of the speed ratio control
parameter is performed so as to bring the acceleration response
close to the target acceleration response on the basis of the
comparison result information between the measured acceleration
response and the target acceleration response calculated as
mentioned above. Therefore, the acceleration response close to the
target acceleration response can be obtained always under the
condition that the vehicle response characteristics are
changed.
According to the sixth structure of the present invention, the
comparison of the acceleration response is performed by using the
index values of the acceleration response time and of the
down-shock magnitude. Therefore, an acceleration response with a
short response time and a small down-shock magnitude is
available.
According to the seventh structure of the present invention, at
least one of calculation of the target acceleration response and
changing of the speed ratio control parameter is performed using
fuzzy logic rules. Therefore, the target acceleration response
which finely corresponds to the vehicle velocity and throttle
opening or the speed ratio control parameter variation can be
calculated.
The foregoing and other objects, advantages, manner of operation
and novel features of the present invention will be understood from
the following detailed description when read in connection with the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of an embodiment of the present
invention, FIG. 2 shows a target primary pulley revolution speed
curve diagram, FIGS. 3 to 7 show membership functions of this
embodiment, FIG. 8 shows a relation curve between the speed ratio
and the stationary step motor position, FIG. 9 is a detailed flow
chart of the processing procedure of a processing block 105, FIG.
10 is a performance comparison diagram between the control method
of the present invention and the conventional control method, FIG.
11 is a block diagram of the second embodiment of the present
invention, FIG. 12 is a block diagram of a continuously variable
transmission, FIGS. 13 and 16 are microcomputer processing flow
charts, FIG. 14 is an engine with a super judger torque variation
characteristic diagram, FIG. 15 is a target primary pulley
revolution speed characteristic diagram, FIGS. 17 and 18 show
membership functions of fuzzy logic rules 1, 2, and 3, FIGS. 20 and
21 show membership functions of fuzzy logic rules 4 and 5, FIG. 19
is a relational curve between the speed ratio and the stationary
step motor position, FIG. 22 is a comparison diagram between the
acceleration waveform of this embodiment at the time of kickdown
and the acceleration waveform when only the conventional speed
ratio control is used, FIG. 23 is a block diagram of the third
embodiment of the present invention, FIG. 24 is a microcomputer
processing flow chart, FIGS. 25 and 26 show membership functions of
fuzzy rules 6 and 7, FIG. 27 is a control performance comparison
chart, FIG. 28 is a block diagram of the fourth embodiment of the
present invention, FIG. 29 shows gear shift lines for four-speed
automatic transmission, FIG. 30 is a microcomputer processing flow
chart, FIG. 31 is an illustration for changing the membership
functions of the fuzzy rules 4 and 5, FIG. 32 is a difference
diagram of the acceleration response when kicked down when the
speed ratio velocity setting is changed, FIG. 33 is a block diagram
of the fifth embodiment of the present invention, FIG. 34 is a
block diagram of a continuously variable transmission, FIG. 35
shows the processing outline of a microcomputer, FIGS. 36, 38, and
44 are microcomputer processing flow charts, FIG. 37 is a target
primary pulley revolution speed characteristic diagram, FIGS. 39
and 40 show membership functions of fuzzy logic rules 1, 2, and 3,
FIG. 41 is a relational curve between the speed ratio and the
stationary step motor position, FIGS. 42 and 43 show membership
functions of fuzzy rules 5 and 6, FIG. 45 is an engine output
torque characteristic diagram, FIGS. 46 and 47 show membership
functions of fuzzy logic rules 8, 9, and 10, FIGS. 48 and 49 show
membership functions of fuzzy logic rules 11 and 12, and FIG. 50 is
a comparison diagram between the conventional control method and
the control method of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Next, the first embodiment of the present invention will be
described with reference to FIGS. 1 to 10.
FIG. 1 shows the structure of this embodiment. In a vehicle which
is driven by transmitting the drive force of an engine 1, which is
a power source, to a drive wheel 5 via a clutch 2, a torque
converter 3, and a hydraulic drive belt type continuously variable
transmission 4, a microcomputer 8 obtains and outputs a control
instruction value 24 to a step motor 9 on the basis of throttle
opening information 21 measured by driver's operation sensors 6,
vehicle velocity information 22 measured by vehicle running status
sensors 7, and revolution speed information 23 of a primary pulley
17 of the continuously variable transmission 4. The speed ratio
mechanism by the step motor 9 is the same type as that indicated in
Japanese Patent Application Laid-Open No. 198447553 and well known.
The step motor 9 decreases the speed ratio (output side belt
running diameter/input side belt running diameter or revolution
speed of the primary pulley 17/revolution speed of the secondary
pulley 18) by moving a speed ratio control valve 12 via a converter
10 and a valve rod 11 and inserting high pressure oil into a
movable half of the primary pulley 19 of the continuously variable
transmission 4 or increases the speed ratio by returning the oil
from the movable half of the primary pulley 19 to a reservoir 15.
One end of the valve rod 11 is in contact with the inner conical
surface of the movable half of the primary pulley 19 and the other
end of the valve rod 11 is in contact with a shaft 20 of the
converter 10. The drive torque of the continuously variable
transmission 4 is transmitted sequentially to the primary pulley
17, a metal belt 16, and the secondary pulley 18. Next, the
processing contents of the microcomputer 8 which is an essential
section of this patent will be described.
A rough flow chart of the processing procedure of the microcomputer
8 is shown in FIG. 1. The microcomputer 8 reads the throttle
opening information 21, the vehicle velocity information 22, and
the primary pulley revolution speed information 23 by a measured
data read block 101, calculates the target primary pulley
revolution speed from the throttle opening information 21 and the
vehicle velocity information 22, and goes to a block 102. So as to
calculate the above target primary pulley revolution speed, the
microcomputer 8 stores data of the relational curves between the
target primary pulley revolution speed, vehicle velocity, and
throttle opening shown in FIG. 2 beforehand, and determines the
target primary pulley revolution speed at an optional vehicle
velocity and throttle opening by linear interpolation using those
data. In the deviation judgment block 102, the microcomputer 8
determines the difference e (n.sub.in -nN.degree..sub.in) between
the target primary pulley revolution speed n.sub.in determined by
the block 101 and the primary pulley revolution speed n.sub.in. The
difference is called the deviation. When the absolute value e of
the deviation becomes as follows:
the microcomputer 8 goes to a block 103. When the absolute value is
equal to or more than h.sub.1, the microcomputer 8 goes to a block
104. There are four fuzzy logic rules available, as shown below, in
the target step motor position difference calculation block
103.
(Fuzzy logic rule 1)
When the following are satisfied:
e is negative and small, and
.DELTA.e (e at present "-"e 10 ms before is negative and small,
the microcomputer 8 allows the step motor to run moderately in the
direction where the speed ratio increases.
(Fuzzy logic rule 2)
When the following are satisfied:
{e is positive and small and .DELTA.e is positive and small,
the microcomputer 8 allows the step motor to run moderately in the
direction where the speed ratio decreases.
(Fuzzy logic rule 3)
When the following are satisfied:
{e is zero and .DELTA.e is zero,
the step motor is fixed (1).
(Fuzzy rule 4) ##EQU2##
the step motor is fixed (2).
The microcomputer 8 determines the target step motor position
difference .DELTA.I on the basis of the above four rules, and goes
to a block 105. The target step motor position difference .DELTA.I
is calculated from the following expression: ##EQU3##
Symbols G.sub.i and S.sub.i in the above expression indicate a
gravity center and an area of membership functions N1, P1, and Z1
of the fuzzy logic rules 1 to 3 such as:
the microcomputer 8 allows the step motor to run moderately in the
direction where the speed raio increases,
the microcomputer 8 allows the step motor to run moderately in the
direction where the speed raio decreases, and
the step motor is fixed (1).
A symbol y.sub.i (i=1, 2, and 3) indicates the adaptation of each
of the rules 1 to 3. When the adaptation at e and .DELTA.e of the
membership functions SNE, SNDE, SPE, SPDE, ZRE, and ZRDE of the
fuzzy rules 1 to 3 shown below:
e is negative and small,
.DELTA.e is negative and small,
e is positive and small,
.DELTA.e is positive and small,
e is zero, and
.DELTA.e is zero,
is expressed by x.sub.1, x.sub.2, x.sub.3, x.sub.4, x.sub.5, and
x.sub.6, the adaptation yi is determined by the following
expressions:
The adaptation for each membership function means a vertical
coordinate value corresponding to a transverse coordinate value
when the membership function is considered as a mapping function
wherein a vertical coordinate value (adaptation 0 to 1) corresponds
to a variable of the transverse coordinate. FIG. 3 shows the
membership functions N1, Z1, and P1, and the transverse coordinate
indicates the step count variation of the step motor. FIG. 4 (A)
shows the membership functions SNE, ZRE, and SPE, and the
transverse coordinate indicates the deviation e [rpm]. FIG. 4 (B)
shows the membership functions SNDE, ZRDE, and SPDE, and the
transverse coordinate indicates the deviation difference .DELTA.e
[rpm]. A coefficient of k.sub.2 in the expression for determining
the target step motor position difference .DELTA.I is determined
from the following expression:
when the adaptation at e and .DELTA..theta. of the membership
functions SAE and SATH of the fuzzy rule 4 shown below:
.vertline.e.vertline. is small, and
.vertline..DELTA..theta..vertline. is small,
is expressed by x.sub.7 and x.sub.8. FIG. 5 (A) shows the
membership function SAE, and the transverse coordinate indicates
.vertline.e.vertline. [rpm]. FIG. 5 (B) shows the membership
function SATH, and the transverse coordinate indicates
.vertline..DELTA..theta..vertline. [degree]. There are four fuzzy
rules available, as shown below, in the target step motor position
difference calculation block 104.
(Fuzzy logic rule 5)
When the following are satisfied: ##EQU4##
{e is negative and large and T is small, or
e is positive and large and T is medium,
the microcomputer 8 allows the step motor to run largely in the
direction where the speed raio increases.
(Fuzzy logic rule 6)
When the following are satisfied:
{e is positive and large and T is large, or
{e is positive and large and T is small, or
{e is negative and large and T is medium,
the microcomputer 8 allows the step motor to run largely in the
direction where the speed raio decreases.
(Fuzzy logic rule 7) ##EQU5##
{e is negative and large and .DELTA..sup.2 .nu. is negative and
small,
the microcomputer 8 decreases the running of the step motor for
changing the speed ratio.
(Fuzzy logic rule 8) ##EQU6## negative and large,
the microcomputer 8 does not correct the running of the step motor
for changing the speed ratio.
The microcomputer 8 determines the target step motor position
difference .DELTA.I on the basis of the above four rules, and goes
to the block 105. The target step motor position difference
.DELTA.I is calculated from the following expression: ##EQU7##
Symbols G.sub.j, S.sub.j, G.sub.k, and S.sub.k in the above
expression indicate a gravity center and an area of membership
functions N2, P2, M1, and M2 of the fuzzy rules 5 to 8 such as:
the microcomputer 8 allows the step motor to run largely in the
direction where the speed ratio increases,
the microcomputer 8 allows the step motor to run largely in the
direction where the speed ratio decreases,
the microcomputer 8 decreases the running of the step motor for
changing the speed ratio, and
the microcomputer 8 does not correct the running of the step motor
for changing the speed ratio.
Symbols y.sub.j (j=5 and 6) and y.sub.k (k=7 and 8) indicate the
adaptation of each of the rules 5 to 8. When the adaptation at e,
T, and .DELTA..sup.2 .nu. of the membership functions BNE, BPE, BT,
MT, ST, BNDV, SNDV, SPDV, and BPDV of the fuzzy logic rules 5 to 8
shown below:
T is large,
T is medium,
T is small,
.DELTA..sup.2 .nu. is negative and large,
.DELTA..sup.2 .nu. is negative and small,
.DELTA..sup.2 .nu. is positive and small, and
.DELTA..sup.2 .nu. is positive and large,
is expressed by x.sub.7, x.sub.8, x.sub.9, x.sub.10, x.sub.11,
x.sub.12, x.sub.13, x.sub.14, and x.sub.15, the adaptation y.sub.j
or y.sub.k is determined by the following expressions:
FIG. 6 (A) shows the membership functions N2 and P2, and the
transverse coordinate indicates the step count variation of the
step motor. FIG. 6 (B) shows the membership functions M1 and M2,
and the transverse coordinate indicates a nondimensional
coefficient. FIG. 7 (A) shows the membership functions BNE and BPE,
and the transverse coordinate indicates the deviation e [rpm]. FIG.
7 (B) shows the membership functions ST, MT, and BT, and the
transverse coordinate indicates T (the number of steps). FIG. 7 (C)
shows the membership functions BNDV, SNDV, SPDV, and BPDV, and the
transverse coordinate indicates .DELTA..sup.2 .nu. [km/h]. Symbols
L.sub.o and L.sub.a which are used for calculation of T are
determined as shown below. L.sub.a is determined by the step motor
operation quantity calculation block 105 10 ms before. As to
L.sub.o, the speed ratio i is calculated from the following
expression first: ##EQU8##
(.nu.[km / h]: vehicle velocity)
and L.sub.o is determined by linear interpolation using the
relational curve date between the speed ratio i and "i-L.sub.o "
which is stored in the microcomputer 8 beforehand. FIG. 8 shows a
relational curve between i (speed ratio) and L.sub.o (balanced step
motor position in the stationary state).
FIG. 9 shows a detailed flow chart of the processing procedure of
the step motor operation quantity calculation block 105. The
microcomputer 8 calculates:
in a block 201 and goes to a block 202. The microcomputer 8 makes a
branching judgment that when k.sub.3 -1.ltoreq.I.ltoreq.k.sub.3
(k.sub.3 : a constant between 0 and 1) in the block 202, it goes to
a block 203 or in other cases, it goes to a block 204. In the block
23, the microcomputer 8 inputs
at the address of the operation instruction flag (SMFLAG) of the
step motor and goes to a block 106. In the block 204, the
microcomputer 8 makes a condition branching judgment; that is, when
I>k.sub.3, it goes to a block 205 or in other cases, it goes to
the block 206. In the block 205, the microcomputer 8 performs the
following processing:
and goes to the block 106. In the block 206, the microcomputer 8
performs the following processing:
and goes to the block 106. In the operation quantity output block
106, the microcomputer 8 goes and checks the value of the operation
quantity instruction flag (SMFLAG). When the value is 0, the
microcomputer 8 issues the instruction 24 for keeping the step
motor off. When the value is 1, the microcomputer 8 issues the
instruction 24 for rotating the step motor by one step so as to
decrease the speed ratio. When the value is -1, the microcomputer 8
issues the instruction 24 for rotating the step motor by one step
so as to increase the speed ratio. A series of processing from the
block 101 to the block 106 is performed once every 10 ms. For
comparison between the control method of the present patent and the
conventional proportion and integration control method (the
operation quantity is calculated by proportion and integration of
the deviation e in the blocks 102 to 104 of this method), the
vehicle acceleration and engine revolution speed responses when
kicked down during stationary running of 40 km/h are shown in FIG.
10. FIG. 10 shows that by using the control method of the present
patent, the acceleration is changed smoothly (free of down-shock
and up-shock), the engine revolution speed is not overshot, the
drivability is improved, and the fuel expense is lowered.
Next, the second embodiment of the present invention will be
described with reference to FIGS. 11 to 22.
FIG. 11 shows the structure of this embodiment. In a vehicle which
is driven by transmitting the drive force of an engine 211, which
is a power source, to a drive wheel 411 via a continuously variable
transmission 311, a microcomputer 511 calculates an operation
instruction 4111 to an actuator I (electromagnetic clutch) 3111 and
an operation instruction 4211 to an actuator II (step motor) 3211
on the basis of four types of information such as engine revolution
speed information 231, throttle opening information 241, primary
pulley revolution speed information 251, and secondary pulley
revolution speed information which are outputs from running status
sensors (a sensor I131 (engine revolution speed sensor), a sensor
II141 (throttle opening sensor), a sensor III151 (primary pulley
revolution speed sensor), and a sensor IV161 (secondary pulley
revolution speed sensor) and outputs the instructions to the
actuators. The actuator I3111 adjusts the charging efficiency
(intake air weight / air weight under the standard condition) to
the engine cylinders by turning between a super charger of the
engine 211 and a shaft, which rotates via a belt from the engine
crank shaft, ON or OFF on the basis of the operation instruction
4111 and controls the engine output. The actuator II3211 controls
the speed ratio of the continuously variable transmission 311 on
the basis of the operation instruction 4211. The engine 211 is an
ordinary engine having a super charger and an electronic fuel
injection system, and the transmission 311 has the structure shown
in FIG. 12. The speed ratio mechanism by the actuator II3211 on the
basis of the operation instruction 4211 is the same type as that
indicated in Japanese Patent Application Laid-Open No. 1984-47553
and well known. The actuator II3211 decreases the speed ratio
(output side belt running diameter/input side belt running diameter
or revolution speed of a primary pulley 57/revolution speed of a
secondary pulley 58) by pouring high pressure oil into the primary
pulley 57 of the continuously variable transmission 311 by
operating a speed ratio control valve 50 via a converter 54 and a
valve rod 59 or increases the speed ratio by returning the oil from
the primary pulley 57 to a reservoir 53. One end of the valve rod
59 is in contact with the inner conical surface of the movable half
of the primary pulley 57 and the other end of the valve rod 59 is
in contact with a shaft 64 of the converter 54. The drive torque of
the continuously variable transmission 311 is transmitted
sequentially to the primary pulley 57, a metal belt 56, and the
secondary pulley 18. Next, the processing contents of the
microcomputer 511 which is an essential section of this patent will
be described.
The processing of the microcomputer 511 is outlined in FIG. 11. The
microcomputer 511 calculates the acceleration variation predicted
value in a vehicle acceleration variation prediction processor 1101
using engine revolution speed information 231, primary pulley
revolution speed information 251, and secondary pulley revolution
speed information 261, calculates the operation instruction value
in an operation quantity calculation processor 1102 to the actuator
I on the basis of this predicted value, outputs the operation
instruction 4111, calculates the target primary pulley revolution
speed in a target primary pulley revolution speed calculation
processor 1104 using the throttle opening information 241 and the
secondary pulley revolution speed information 261, calculates the
operation instruction value in an operation instruction calculation
processor 1107 to the actuator II on the basis of this target
primary pulley revolution speed, the primary pulley revolution
speed information 251, the secondary pulley revolution speed
information 261, and the past operation instruction 4211, and
outputs an operation instruction 4211. The above series of
processing of the microcomputer 511 is performed every 0.01
seconds.
FIG. 13 shows a detailed processing flow chart of the vehicle
acceleration variation prediction processor 1101 and the operation
instruction calculation processor 1102 to the actuator I. In the
processor 201, using the measured values at this time:
n.sub.e (0): engine revolution speed,
n.sub.in (0): primary pulley revolution speed, and
n.sub.out (0): secondary pulley revolution speed,
and the measured values n.sub.e (-k) , n.sub.in (-k) , and
n.sub.out (-k) k.times.0.01 (k=1, 2) seconds before, the
microcomputer 511 determines the predicted values of engine
revolution speed, speed ratio, and speed ratio velocity T.sub.1
=0.02 seconds later from the following expressions: ##EQU9## and
goes to the processor 202. In the processor 202, the microcomputer
511 determines a vehicle acceleration variation index value S:
##EQU10## where: Ie: Moment of inertia from the engine to the
primary pulley, and goes to the processor 203. In the processor
203, the microcomputer 511 determines necessary correction torque
.DELTA.Te:
and goes to the processor 204. In the processor 204, the
microcomputer 511 determines a clutch connection correction time
.DELTA.D: ##EQU11##
where: D.sub.o : Standard clutch ON,
by interpolation using the measured value .theta.(0) at this time
(throttle opening), .DELTA.Te, and the clutch connection time and
engine torque characteristic data stored in the n.sub.e *
microcomputer 511 (FIG. 14), and goes to the processor 205. In the
processor 205, the microcomputer 511 determines a total clutch ON
time from the following expression:
The microcomputer 511 outputs the value to the actuator I as an
operation instruction 4111 and goes to the processor 1104 shown in
FIG. 11.
In the target primary pulley revolution speed calculation processor
1104, the microcomputer 511 calculates the target primary pulley
revolution speed n.sub.in from the throttle opening information
24.theta.(0) and the secondary pulley revolution speed information
26n.sub.out (0) using the relational curves shown in FIG. 15, and
goes to the next processor 1107. FIG. 16 shows a detailed
processing flow chart of the operation instruction calculation
processor 1107 to the actuator II. In a deviation judgment section
401, the microcomputer 511 determines the difference e
(n.degree..sub.in (0)-n.sub.n.degree..sub.in) between the target
primary pulley revolution speed n.degree..sub.in and the primary
pulley revolution speed n.sub.in (0). When the absolute value e
satisfies the following expression:
the microcomputer 511 goes to a processor 402. In other cases, the
microcomputer 511 goes to a processor 403. In the processor 402,
the microcomputer 511 determines .DELTA.e "e at present"--"e
obtained 0.01 seconds before". There are three fuzzy logic rules
available as shown below.
(Fuzzy logic rule 1)
When the following are satisfied: ##EQU12##
the microcomputer 511 allows the step motor to run a little in the
direction where the speed raio increases.
(Fuzzy logic rule 2)
When the following are satisfied: ##EQU13##
the microcomputer 511 allows the step motor to run a little in the
direction where the speed raio decreases.
(Fuzzy logic rule 3)
When the following are satisfied: ##EQU14##
the step motor is fixed.
The microcomputer 511 determines the first target value .DELTA.I of
step motor movement on the basis of the above three rules, and goes
to a processor 404.
The first target value .DELTA.I is determined from the following
expression: ##EQU15##
Symbols G.sub.i and S.sub.i in the above expression indicate a
gravity center and an area of the membership functions (see FIG.
17) of the fuzzy logic rules 1 to 3 such as:
the microcomputer 511 allows the step motor to run a little in the
direction where the speed raio increases (N1),
the microcomputer 511 allows the step motor to run a little in the
direction where the speed raio decreases (P1), and
the step motor is fixed (Z1).
A symbol y.sub.i indicates the adaptation of each of N1, P1, and
Z1. When the adaptation at e and .DELTA.e of the membership
functions of the fuzzy logic rules 1 to 3 shown below:
e is positive and small (SPE),
.DELTA.e is positive and small (SPDE),
e is negative and small (SNE),
.DELTA.e is negative and small (SNDE),
e is zero (ZRE), and
.DELTA.e is zero (ZRDE),
is expressed by x.sub.1, x.sub.2, x.sub.3, x.sub.4, x.sub.5, and
x.sub.6, the adaptation y.sub.i is determined by the following
expressions (see FIG. 18):
The adaptation for each membership function means a vertical
coordinate value corresponding to a transverse coordinate value
when the membership function is considered as a mapping function
from transverse coordinate values to vertical coordinate values
(adaptation 0 to 1).
In the processing step 403, the microcomputer 511 determines the
the step motor position L.sub.p, which is stationary at the current
speed ratio i(0)=n.degree..sub.in (0)/n.sub.out (0), using the
relation shown in FIG. 19, determines e (n.sub.in (0)/n.sub.in) and
.DELTA.e "e at present"--"e obtained 0.01 seconds before", and
calculates a step motor control index value Tp using the current
position L.sub.s of the step motor which is obtained in the
processor 411 0.01 seconds before: ##EQU16##
There are two fuzzy logic rules available as shown below.
(Fuzzy logic rule 4)
When the following are satisfied:
e is negative and large, and Tp is positive, or
e is negative and large, and Tp is negative and large, or
e is positive and large, and Tp is positive and small,
the microcomputer 511 allows the step motor to run in the direction
where the speed raio increases.
(Fuzzy rule 5)
When the following are satisfied:
e is positive and large, and Tp is negative, or
e is positive and large, and Tp is positive and large, or
e is positive and large, and Tp is positive and small,
the microcomputer 511 allows the step motor to run in the direction
where the speed raio decreases.
The microcomputer 511 determines the first target value .DELTA.I of
step motor movement on the basis of the above two rules, and goes
to a processor 404. The first target value .DELTA.I is determined
from the following expression: ##EQU17## Symbols G.sub.j and
S.sub.j in the above expression indicate a gravity center and an
area of the membership functions (see FIG. 20) of the fuzzy logic
rules 4 and 5 such as:
the microcomputer 511 allows the step motor to run in the direction
where the speed raio increases (N2), and
the microcomputer 511 allows the step motor to run in the direction
where the speed raio decreases (P2). A symbol y.sub.j indicates the
adaptation of each of N2 and P2. When the adaptation at e and T of
the membership functions of the fuzzy logic rules 4 and 5 shown
below:
e is negative and large (BNE),
e is positive and large (BPE),
Tp is negative (NT),
Tp is positive (PT) ,
Tp is negative and large (BNT),
Tp is positive and large (BPT),
T is negative and small, and
Tp is positive and small (SPT),
is expressed by x.sub.7, x.sub.8, x.sub.9, x.sub.10, x.sub.11,
x.sub.12, x.sub.13, and x.sub.14, the adaptation y.sub.j is
determined by the following expressions (see FIG. 21):
The microcomputer 511 calculates:
in the processor 404 and goes to the next processor 405.
The microcomputer 511 makes a branching judgment that when k.sub.2
-1.ltoreq.I.ltoreq.k.sub.2 (k.sub.2 : a constant between 0 and 1)
in the processor 405, it goes to the processor 406 or in other
cases, the microcomputer 511 goes to the processor 407.
In the processor 406, the microcomputer 511 inputs "SMFLAG 0" at
the address of the operation instruction flag (SMFLAG) of the
actuator II.
In the processor 407, the microcomputer 511 makes a condition
branching judgment; that is, when I>k.sub.2, it goes to the
processor 408 or in other cases, it goes to the processor 409.
In the processor 408, the microcomputer 511 performs the following
processing:
and goes to the processor 410.
In the processor 409, the microcomputer 511 performs the following
processing:
In the processor 410, the microcomputer 511 goes and checks the
value of the operation quantity instruction flag (SMFLAG). When the
value is 0, the microcomputer 511 issues the operation instruction
4211 for keeping the actuator II off. When the value is 1, the
microcomputer 511 issues the operation instruction 4211 for
rotating the actuator II by one step so as to decrease the speed
ratio. When the value is -1, the microcomputer 511 issues the
operation instruction 4211 for rotating the actuator II by one step
so as to increase the speed ratio. Then, the microcomputer 511 goes
to the processor 411. In the processor 411, the microcomputer 511
performs the following processing:
For comparison of the control method of this embodiment only with
the speed ratio control of the conventional proportion and
integration control method (the operation quantity is calculated by
proportion and integration of e in the processor 1107 of this
method), the vehicle acceleration responses when kicked down and
foot up during stationary running of a vehicle velocity of 40 km/h
are shown in FIG. 22. FIG. 22 shows that by using this control
method, the acceleration is changed smoothly (free of down-shock
and up-shock) and the promptness is improved.
The third embodiment of the present invention will be described
with reference to FIGS. 23 to 27. FIG. 23 shows the structure of
this embodiment. The differences from the second embodiment are
that a sensor V (back and forth acceleration sensor) 171 is used in
place of the sensor I (engine revolution speed sensor) 131 and a
driving axle torque variation prediction processor 1108 and an
operation instruction calculation processor 1109 to the actuator I
are used for processing of the microcomputer 511 in place of the
vehicle acceleration variation prediction processor 1101 and the
operation instruction calculation processor 1102 to the actuator I.
Next, the flow chart of the processing procedure of the
microcomputer 511 which is different from that of the second
embodiment will be described.
FIG. 24 shows a detailed processing flow chart of the driving axle
torque variation prediction processor 1108 and the operation
instruction calculation processor 1109 to the actuator I. In a
processor 301, the microcomputer 511 determines the moving average
(output of the low-pass filter) from time series data of
acceleration information 271 detected by the back and forth
acceleration sensor 171 shown in FIG. 23:
(Acceleration measured "k.times.-0.01" seconds before) using:
##EQU18## and determines the predicted value a* of the vehicle back
and forth acceleration with the body vibration component excluded
T.sub.1 seconds later from:
and goes to a processor 302. "a(-4)" in the above expression
indicates a moving average calculated 0.04 seconds before. In the
processor 302, the microcomputer 511 determines a driving axle
torque variation index value H from the following expression:
and goes to a processor 303. A symbol I.sub.co indicates moment of
inertia for the system from the secondary pulley to the drive
wheel+vehicle inertial reflected at the driving axle. In the
processor 303, the microcomputer 511 determines .DELTA..theta.
(throttle opening .theta.(0) measured at this time throttle opening
.theta.(-100) calculated 1 second before) and .DELTA.t*=H.n.sub.out
(0)/ n.sub.in (0).
There are three fuzzy logic rules available as shown below.
(Fuzzy logic rule 6)
When .DELTA..theta. is positive and .DELTA.T* is negative: the
coefficient .DELTA.T is negative.
When .DELTA..theta. is negative and .DELTA.T* is positive: the
coefficient .DELTA.T is negative.
(Fuzzy logic rule 7)
When .DELTA..theta. is positive and .DELTA.T* is positive: the
coefficient .DELTA.T is zero.
When .DELTA..theta. is negative and .DELTA.T* is negative: the
coefficient .DELTA.T is zero.
On the basis of the above three rules, the microcomputer 511
determines necessary correction engine torque .DELTA.T from the
following expression:
and goes to the processor 204. The coefficient .DELTA.T is
determined from the following expression: ##EQU19## Symbols G.sub.i
and S.sub.i in the above expression indicate a gravity center and
an area of the membership functions (see FIG. 25) of the fuzzy
logic rules 6 and 7 such as:
A symbol y.sub.i indicates the adaptation of each of NC.DELTA.T and
ZRC.DELTA.T. When the adaptation at .DELTA..theta. and .DELTA.T* of
the membership functions of the fuzzy logic rules 6 and 7 shown
below:
.DELTA..theta. e is negative (NTH),
.DELTA..theta. is positive (PTH),
.DELTA.T* is negative (NTR), and
.DELTA.T* is positive (PTR),
is expressed by x.sub.15, x.sub.16, x.sub.17, and x.sub.18, the
adaptation y.sub.i is determined by the following expressions (see
FIG. 26):
The other processing of the microcomputer 511 is the same as that
of the second embodiment. Therefore, the description thereof will
be omitted.
For comparison between the control method of this third embodiment
and the conventional control method, the vehicle acceleration
responses when kicked down and foot up during stationary running of
a vehicle velocity of 40 km/h are shown in FIG. 27. The drawing
shows that by using this control method, the acceleration is
changed smoothly and the promptness is superior. Although the
promptness is inferior to that of the second embodiment, the
request level for the engine torque control is low.
In the second and third embodiments, the engine torque is adjusted
by super charger control. However, the engine torque may be
adjusted by fuel injection quantity control, ignition timing
control, or electronic throttle control.
The fourth embodiment o#the present invention will be described
with reference to FIGS. 28 to 32. FIG. 28 shows the structure of
this embodiment. The differences from the second embodiment are
that the actuator I (electromagnetic clutch) 3111 is removed and an
apparatus for inputting stationary speed ratio characteristics 2811
and an apparatus for inputting transient speed ratio
characteristics 2812 are additionally installed in place of the
sensor I (engine revolution speed sensor) 131. The apparatus for
inputting stationary speed ratio characteristics 2811 outputs
information for setting the ratio of speed ratio characteristics
2111 in accordance with the position setting by the slide volume of
a driver 281. The apparatus for inputting transient speed ratio
characteristics 2812 outputs speed ratio velocity setting
information 2211 in accordance with the position setting by another
slide volume of the driver 281. The microcomputer 511 calculates
the operation quantity to the actuator II (step motor) 3211 using
the information for setting the ratio of speed ratio
characteristics 2111, the speed ratio velocity setting information
2211, the throttle opening information 241, the primary pulley
revolution speed information 251, and the secondary pulley
revolution speed information 261, and outputs the operation
instruction 4211. The operation of the actuator II3211 is the same
as that of the second embodiment. Next, the processing contents of
the microcomputer 511 which is an essential section of this patent
will be described.
A rough flow chart of the processing of the microcomputer 511 is
shown in FIG. 28. In a processor for setting the ratio of speed
ratio characteristics for the continuously variable transmission
and the finite speed automatic transmission 1103, the microcomputer
511 stores that the driver's desire ratio of the speed ratio
characteristics for the continuously variable transmission to the
speed ratio characteristics for the finite speed automatic
transmission is (1-.alpha.): .alpha. on the basis of the value
.alpha. (0.ltoreq..alpha..ltoreq.1) of the information for setting
the ratio of speed ratio characteristics 2111, and goes to a target
primary pulley revolution speed calculation processor 1110. In the
processor 1110, the microcomputer 511 calculates the target primary
pulley revolution speed n.sub.in 1 for .alpha.=0 from the
relational curves shown in FIG. 15, the throttle opening
information 241, and the secondary pulley revolution speed
information 261, calculates the target primary pulley revolution
speed n.sub.in 2 for .alpha.=1, and a current speed among four
speeds from information indicating one of the characteristic line
diagram shown in FIG. 29 and a speed among four speeds obtained
0.005 seconds before, the throttle opening information 241, and the
secondary pulley revolution speed information 261, and determines
the target primary pulley revolution speed n.degree..sub.in finally
from the following expression:
and goes to a processor for calculating necessary predicting time
for reaching the target speed ratio 1105. In the processor 1105,
the microcomputer 511 determines the necessary predicting time for
reaching the target speed ratio NS from the primary pulley
revolution speed information 251n.sub.in (0) and the target primary
pulley revolution speed information using the following expression:
##EQU20## where:
and
e(-1)=e(0) obtained 0.005 seconds before, and goes to a speed ratio
velocity correction processor 1106. FIG. 30 shows a detailed
processing flow chart of the processors 1106 and 1111. The only one
difference from the processing of the processor 1107 (FIG. 16) in
the second embodiment is that a membership function changing
section 301 is added. In the membership function changing section
301, the microcomputer 511 moves the membership functions SNT and
SPT of the fuzzy rules 5 and 6 continuously to the right or left by
linear interpolation on the basis of the value .beta.
(0.ltoreq..beta..ltoreq.1) of the speed ratio velocity setting
information 2211 (the cases of .beta.=0.05 and 1 are shown in FIG.
31). The transverse coordinate value T of each of the membership
functions is determined from the following expression using the
necessary predicting time for reaching the target speed ratio NS
obtained in the processor 1105:
The operations of the other processors are the same as those of the
second embodiment. Therefore, the description thereof will be
omitted. The vehicle acceleration responses when kicked down during
running of 40 km/h when the value .beta. of the speed ratio
velocity setting information 2211 is 0.05 or 1 in this embodiment
are shown in FIG. 32.
In this embodiment, the four-speed automatic transmission shown in
FIG. 29 is used as a speed ratio characteristic for the finite
speed automatic transmission. However, threespeed, five-speed, or
more-speed automatic transmission may be used, and selection of the
number of speeds by a driver can be easily realized by using an
interface such as a CRT.
Finally, the fifth embodiment of the present invention will be
described with reference to FIGS. 33 to 50.
FIG. 33 shows the structure of this embodiment. In a vehicle which
is driven by transmitting the drive force of an engine 211, which
is a power source, to a drive wheel 411 via a continuously variable
transmission 311, the microcomputer 511 calculates an operation
instruction 3318 to an actuator (step motor) 3011 and a change
value 3326 of the control parameter which is used for calculation
of the above operation instruction 3318 on the basis of four types
of information such as throttle opening information 231, secondary
pulley revolution speed information 241, primary pulley revolution
speed information 251, and engine revolution speed information 261
which are outputs from running status sensors (a sensor I131
(throttle opening), a sensor II141 (engine revolution speed
sensor), a sensor III151 (primary pulley revolution speed sensor),
and a sensor IV161 (output pulley revolution speed sensor), outputs
the instruction to the actuator 3011, and changes the control
parameter of the operation instruction calculation processor 3103
to the actuator according to the change value 3326.
The actuator 3011 controls the speed ratio of the continuously
variable transmission 311 on the basis of the operation instruction
3318 calculated by the microcomputer 511.
The speed changing method of the continuously variable transmission
311 using the actuator 3011 is the same type as that indicated in
Japanese Patent Application Laid-Open No. 1984-47553 as shown in
FIG. 34. The actuator 3011 decreases the speed ratio (output side
belt running diameter / input side belt running diameter or
revolution speed n.sub.in of a primary pulley 3457/revolution speed
n.sub.out of a secondary pulley 3458) by pouring high pressure oil
into the primary pulley 3457 of the continuously variable
transmission 311 by operating a speed ratio control valve 3450 via
a converter 3454 and a valve rod 3455 or increases the speed ratio
by returning the oil from the primary pulley 3457 to a
reservoir.
One end of the valve rod 3455 is in contact with the inner conical
surface of the movable half 3460 of the primary pulley 3457 and the
other end of the valve rod 3455 is in contact with a shaft 3459 of
the converter 3454.
The drive torque of the continuously variable transmission 311 is
transmitted sequentially to the primary pulley 3457, a metal belt
3456, and a secondary pulley 3458.
Next, the processing contents of the microcomputer 511 which is an
essential section of the present invention will be described with
reference to FIGS. 33 and 35.
Using the throttle opening information 231, the engine revolution
speed information 241, the primary pulley revolution speed
information 251, and the secondary pulley revolution speed
information 261, the microcomputer 511 makes a condition branching
judgment for whether or not to change the parameter for actuator
operation instruction calculation by the judgment function for
parameter alteration 3101. When changing the parameter, the
microcomputer 511 goes to a processor for calculating an index
value of acceleration response 3104. In other cases, the
microcomputer 511 goes to a processor for calculating a target
primary pulley revolution speed 3102.
In the processor 3104, the microcomputer 511 calculates
acceleration response index values 3322 and 3323, and goes to the
processor 3102 until the calculation of index values 3322 and 3323
is finished. When the calculation of index values is finished, the
microcomputer 511 goes to a memory of index value for target
acceleration response 3105, a processor for comparing acceleration
response 3106, and a processor for control parameter alteration
3107.
In the processor 3105, the microcomputer 511 calculates target
index values 3320 and 3321.
In the processor 3106, the microcomputer 511 compares the index
values 3322 and 3323 calculated in the processor 3104 with the
target index values 3320 and 3321.
In the processor 3107, the microcomputer 511 changes the parameter
to be used for actuator operation instruction calculation on the
basis of comparison results 3324 and 3325 and goes to the processor
3102.
In the processor for calculating target primary pulley revolution
speed 3102, the microcomputer 511 calculates a target primary
pulley revolution speed 3317. In the processor for calculating
actuator operation instruction 3103, the microcomputer 511
calculates an operation instruction value to the actuator on the
basis of the target primary pulley revolution speed 3317, the
primary pulley revolution speed information 251, the secondary
pulley revolution speed information 261, and the past operation
instruction 3318, and outputs an operation instruction 3318.
The above series of processing is divided into three parts (1),
(2), and (3) by each condition branch, and all the actuator
operation instructions are performed every 0.01 seconds.
FIG. 36 shows a detailed processing flow chart of the judgment
function for parameter alteration 3101.
In a processor 3601, the microcomputer 511 determines whether the
processing in execution is (1) or (2) mentioned above from the
MFLAG value. When the current processing is (1) (MFLAG=0), the
microcomputer 511 goes to a processor 3602. When the current
processing is (2) (MFLAG=1), the microcomputer 511 goes to a
processor 3606.
In the processor 3602, using the calculated values at this
time:
.theta.(0): throttle opening,
n.sub.in (0): primary pulley revolution speed, and
n.sup.out (0): secondary pulley revolution speed, and the measured
values (-5), n.sub.in (-5), and n.sub.out (-5) 0.5 seconds before,
the microcomputer 511 calculates the following:
and goes to a processor 3603.
In the processor 3603, the microcomputer 511 determines whether
.DELTA..theta. and DI satisfy the following conditions:
When they satisfy the conditions, the microcomputer 511 goes to a
processor 3604. In other cases, the microcomputer 511 goes to a
processor 3608.
In the processor 3608, the microcomputer 511 leaves the MFLAG value
0 unchanged and goes to the processor for calculating target
primary pulley revolution speed 3102.
In the processor 3604, the microcomputer 511 stores the time t(0),
which satisfies the conditions in the processor 3603, .theta.(0) at
that time, and n.sub.out (0) as shown below. ##STR1## and sets:
and goes to the processor for calculating acceleration response
index value 3104.
In the processor 3606, the microcomputer 511 calculates the
difference D.theta. between .theta.T, which is stored in the
processor 3604, and the throttle opening at this time:
and goes to a processor 3607.
In the processor 3607, the microcomputer 511 determines the
following:
When the difference satisfies the condition, the microcomputer 511
goes to the processor for calculating an index value of
acceleration response 3104. In other cases, the microcomputer 511
goes to the processor 3608, sets the following:
and goes to the processor for calculating a target primary pulley
revolution speed 3102.
In the processor for calculating target primary pulley revolution
speed 3102, the microcomputer 511 calculates the target primary
pulley revolution speed n.sub.in 3317 from the throttle opening
information 231 and the secondary pulley revolution speed
information 261 using the relational curves shown in FIG. 37, and
goes to the next processor 3103. FIG. 38 shows a detailed
processing flow chart of the processor for calculating operation
instruction 3103 to the actuator. In a deviation judgment processor
3801, the microcomputer 511 determines the difference e (n.sub.in
-n.degree..sub.in) between the target primary pulley revolution
speed n.degree..sub.in information 3317 and the primary pulley
revolution speed n.sub.in information 251. When the absolute value
.vertline.e.vertline. becomes as follows:
the microcomputer 511 goes to a processor 3802. In other cases, the
microcomputer 511 goes to a processor 3803. In the processor 3802,
the microcomputer 511 determines .DELTA.e "e at present"--"e
obtained 0.01 seconds before". There are three fuzzy logic rules
available as shown below.
(Fuzzy logic rule 1)
When the following are satisfied:
e is positive and small, and
.DELTA.e is positive and small,
the microcomputer 511 allows the step motor to run a little in the
direction where the speed ratio increases.
(Fuzzy logic rule 2)
When the following are satisfied: ##EQU21##
the microcomputer 511 allows the step motor to run a little in the
direction where the speed ratio decreases.
(Fuzzy rule 3)
When the following are satisfied: ##EQU22##
the step motor is fixed.
The microcomputer 511 determines the first target value .DELTA.I of
step motor movement on the basis of the above three rules, and goes
to a processor 3804.
The first target value .DELTA.I is determined from the following
expression: ##EQU23## Symbols G.sub.i and S.sub.i in the above
expression indicate a gravity center and an area of the membership
functions (see FIG. 39) of the fuzzy logic rules 1 to 3 such
as:
the microcomputer 511 allows the step motor to run a little in the
direction where the speed ratio increases (N1),
the microcomputer 511 allows the step motor to run a little in the
direction where the speed ratio decreases (P1), and
the step motor is fixed (Z1).
A symbol y.sub.i indicates the adaptation of each of N1, P1, and
Z1. When the adaptation at e and .DELTA.e of the membership
functions of the fuzzy logic rules 1 to 3 shown below:
e is positive and small (SPE),
.DELTA.e is positive and small (SPDE),
e is negative and small (SNE),
.DELTA.e is negative and small (SNDE),
e is zero (ZRE), and
.DELTA.e is zero (ZRDE),
is expressed by x.sub.1, x.sub.2, x.sub.3, x.sub.4, x.sub.5, and
x.sub.6, the adaptation y.sub.i is determined by the following
expressions (see FIG. 40):
The adaptation for each membership function means a vertical
coordinate value corresponding to a transverse coordinate value
when the membership function is considered as a mapping function
from transverse coordinate values to vertical coordinate values
(adaptation 0 to 1).
In the processor 3803, the microcomputer 511 determines the the
step motor position L.sub.p, which is stationary at the current
speed ratio i=n.sub.in /n.sub.out, using the relation shown in FIG.
41, determines .DELTA.e (n.sub.in /n.degree..sub.in), which is
determined in the processor 3801, and .DELTA.e (value of e "e-0.01"
seconds before), and also calculates a step motor control index
value T using the current position L.sub.s of the step motor which
is obtained in the processor 411 0.01 seconds before:
There are two fuzzy logic rules available as shown below.
(Fuzzy logic rule 4)
When the following are satisfied:
e is negative and large, and T is positive, or
e is negative and large, and T is negative and large, or
e is positive and large, and T is positive and small,
the microcomputer 511 allows the step motor to run in the direction
where the speed ratio increases.
(Fuzzy logic rule 5)
When the following are satisfied:
e is positive and large, and T is negative, or
e is positive and large, and T is positive and large, or
e is positive and large, and T is positive and small,
the microcomputer 511 allows the step motor to run in the direction
where the speed ratio decreases.
The microcomputer 511 determines the first target value .DELTA.I of
step motor movement on the basis of the above two rules, and goes
to the processor 3804. The first target value .DELTA.I is
determined from the following expression: ##EQU24## Symbols G.sub.j
and S.sub.j in the above expression indicate a gravity center and
an area of the membership functions (see FIG. 42) of the fuzzy
logic rules 4 and 5 such as:
the microcomputer 511 allows the step motor to run in the direction
where the speed ratio increases (N2), and
the microcomputer 511 allows the step motor to run in the direction
where the speed ratio decreases (P2).
A symbol y.sub.j indicates the adaptation of each of N2 and P2.
When the adaptation at e and T of the membership functions of the
fuzzy logic rules 4 and 5 shown below:
e is negative and large (BNE),
e is positive and large (BPE),
T is negative (NT),
T is positive (PT),
T is negative and large (BNT),
T is positive and large (BPT),
T is negative and small, and
T is positive and small (SPT),
is expressed by x.sub.7, x.sub.8, x.sub.9, x.sub.10, x.sub.11,
x.sub.12, x.sub.13, and x.sub.14, the adaptation y.sub.j is
determined by the following expressions (see FIG. 43):
The microcomputer 511 calculates the following:
in the processor 3804 and goes to the next processor 3805. The
microcomputer 511 makes a branching judgment that when k.sub.2
-1.ltoreq.I.ltoreq.k.sub.2 (k2: a constant between 0 and 1) in the
processor 3805, it goes to a processor 3806, or in other cases, the
microcomputer 511 goes to a processor 3807.
In the processor 3806, the microcomputer 511 inputs "SMFLAG.rarw.0"
at the address of the operation instruction flag (SMFLAG) of the
actuator.
In the processor 3807, the microcomputer 511 makes a condition
branching judgment; that is, when I<k4 (k4: a constant), it goes
to a processor 3808, or in other cases, the microcomputer 511 goes
to a processor 3809. In the processor 3808, the microcomputer 511
performs the following processing:
and goes to a processor 3810.
In the processor 3809, the microcomputer 511 performs the following
processing:
and goes to the processor 3810.
In the processor 3810, the microcomputer 511 goes and checks the
value of the operation quantity instruction flag (SMFLAG). When the
value is 0, the microcomputer 511 issues an operation instruction
18 for keeping the actuator off. When the value is 1, the
microcomputer 511 issues the operation instruction 18 for rotating
the actuator by one step so as to decrease the speed ratio. When
the value is 1, the microcomputer 511 issues the operation
instruction 18 for rotating the actuator by one step so as to
increase the speed ratio. Then, the microcomputer 511 goes to the
processor 3811.
In the processor 3811, the microcomputer 511 performs the following
processing:
FIG. 44 shows a processing flow chart of the processor for
calculating index value of acceleration response 3104, the memory
of index value for target acceleration response 3105, the processor
for comparing acceleration response 3106, and the processor for
control parameter alteration 3107.
In a processor 4401, using the measured values of the engine
revolution speed information 241, the primary pulley revolution
speed information 251, and the secondary pulley revolution speed
information 261, and the throttle opening information 231 at this
time:
.theta.(0): throttle opening
n.sub.e (0): engine revolution speed,
n.sub.in (0): primary pulley revolution speed, and
n.sub.out (0): secondary pulley revolution speed,
and the measured values .theta. (-n), n.sub.e (-n) , n.sub.in (-n)
, and n.sub.out (-n) n.times.0.01 (n=1, 2, . . . , 11) seconds
before, the microcomputer 511 determines the speed ratio velocity
(di/dt):
and determines the moving average (di/dt)* of 10 values of (di/dt)
0.1 seconds before.
Using the engine output torque T.sub.e calculated from the
relational curves shown in FIG. 45 and the above measured values,
the microcomputer 511 calculates the following:
Ie: Moment of inertia from the engine to the primary pulley
Using the value of h (h(-1)) calculated 0.01 seconds before, the
microcomputer 511 determines the following one by one:
and goes to a processor 4402.
In the processor 4401, when hf<0, the microcomputer 511 ends the
calculation of h and stores h(-1) at this time as a maximum
value.
In the judgment processor 4402, the microcomputer 511 judges
whether the moving average of speed ratio velocity (di/dt)*
satisfies the following condition:
When the moving average does not satisfy the condition, the
microcomputer 511 goes to the processor 3102. This processing is
performed until the condition is satisfied.
When the moving average satisfies the above condition
.vertline.(di/dt)*.vertline.<k.sub.5, the microcomputer 511 goes
to a processor 4404. In the processor 4404, using t obtained by the
judgment function for parameter .theta. alteration 3101, the
microcomputer 511 calculates the following:
t.phi.=Time when .vertline.(di/dt)*.vertline.<k.sub.4 is
satisfied and stores it as acceleration response time index value
information T22. The microcomputer 511 outputs the maximum value of
h obtained in the processor 4401 as acceleration down-shock index
value information H23 and goes to a processor 4405.
In the processor 4405,
the microcomputer 511 performs the processing "MFLAG.rarw.0" and
goes to the memory of target acceleration response 3105.
There are three fuzzy logic rules available in the memory of target
acceleration response 3105.
(Fuzzy logic rule 8)
When .theta.T is large and n.sub.out T is small, the response time
is short and the down-shock is large.
(Fuzzy logic rule 9)
When .theta.T is medium and n.sub.out T is small, or
T is large and n.sub.out T is medium, the response time is medium
and the down-shock is small.
(Fuzzy logic rule 10)
When .theta.T is large and n.sub.out T is large, or
.theta.T is small and n.sub.out T is small, the response time is
long and no down-shock occurs.
Using T15 and n.sub.out T16 calculated by the judgment function for
parameter alteration 3101, the microcomputer 511 calculates target
acceleration response index values T.sub.o 20 and H.sub.o 21 on the
basis of the above three fuzzy logic rules, and goes to the
processor for comparing acceleration response 3106. The index value
T.sub.o is related to the response time and determined from the
following expression: ##EQU25##
Symbols G.sub.1 and S.sub.1 in the above expression indicate a
gravity center and an area of the membership functions (see FIG.
46(A)) of the fuzzy rules 8, 9, and 10 such as:
the response time is short (NTM),
the response time is medium (MTM), and
the response time is long (PTM).
A symbol y.sub.l indicates the adaptation of each of NTM, MTM, and
PTM. When the adaptation at .theta.T and n.sub.out T of the
membership functions of the fuzzy logic rules 8, 9, and 10 shown
below:
.theta.T is small (NTT),
.theta.T is medium (MTT),
.theta.T is large (PTT),
n.sub.out is small (NTT),
n.sub.out is medium (MNT), and
n.sub.out is large (PNT),
is expressed by x.sub.20, x.sub.21, x.sub.22, x.sub.23, x.sub.24,
and x.sub.25, the adaptation y.sub.1 is determined by the following
expressions (see FIG. 47):
The index value H.sub.o is related to down-shock of the
acceleration and determined from the following expression:
##EQU26## Symbols G.sub.l ' and S.sub.l ' in the above expression
indicate a gravity center and an area of the membership functions
(see FIG. 46(B)) of the fuzzy rules 8, 9, and 10 such as:
the down-shock is large (PHK),
the down-shock is small (NHK), and
no down-shock occurs (ZHK).
A symbol y.sub.l indicates the adaptation of each of PHK, NHK, and
ZHK, and can be determined from calculation of the adaptation of
the membership functions .theta.T and n.sub.out T of the fuzzy
logic rules 8, 9, and 10.
In the processor for comparing acceleration response 3106, using
the measured index values T22 and H23 outputted from the processor
for calculating index value of acceleration response 3104 and the
target index values T.sub.o 20 and T.sub.o 21 outputted from the
memory of index value for target acceleration response 3105, the
microcomputer 511 goes to the processor 3107 where the following
values are calculated (.DELTA.T24, .DELTA.T25):
There are two fuzzy logic rules available in the processor for
calculating control parameter alteration 3107.
(Fuzzy logic rule 11)
When .DELTA.T>0 and .DELTA.H.ltoreq.0, the microcomputer 511
changes the control parameter in the direction where the response
time is shortened.
(Fuzzy logic rule 12)
When .DELTA.T<0 and .DELTA.H.ltoreq.0, the microcomputer 511
changes the control parameter in the direction where the response
time is lengthened.
Using the information T24 and T25 outputted from the processor
3106, the microcomputer 511 determines the control parameter
alteration P on the basis of the above two fuzzy logic rules, and
goes to the processor 3102.
The alteration P is determined from the following expression:
##EQU27## Symbols G.sub.m and S.sub.m in the above expression
indicate a gravity center and an area of the membership functions
(see FIG. 48) of the fuzzy logic rules 11 and 12 such as:
the microcomputer 511 changes the control parameter in the
direction where the acceleration response time is shortened (NPM),
and
the microcomputer 511 changes the control parameter in the
direction where the acceleration response time is lengthened
(PPM).
A symbol y.sub.m indicates the adaptation of each of NPM and
PPM.
When the adaptation at .DELTA.T and .DELTA.H of the membership
functions of the fuzzy logic rules 11 and 12 shown below:
.DELTA.T is negative (NPDT),
.DELTA.T is positive (PPDT),
.DELTA.H is less than 0 (NPDH), and
.DELTA.H is more than 0 (PPDH),
is expressed by x.sub.30, x.sub.31, x.sub.32, and x.sub.33, the
adaptation y.sub.m is determined by the following expressions (see
FIG. 49):
On the basis of the calculated parameter alteration P26, the
microcomputer 511 changes the operation instruction calculation
parameter (line segment Pq of the membership function SNT shown in
FIG. 43(B)) to the actuator.
To compare the control method of this embodiment with the
conventional control method, the acceleration waveforms when the
throttle opening is fully opened during stationary running of a
vehicle velocity of 40 km/h when the vehicle weight is increased
(the number of passengers is increased from 1 to 4) is shown in
FIG. 50. Numeral 1 indicates the acceleration waveform at the
normal weight, 2 the acceleration waveform when the conventional
control method is used, and 3 the acceleration waveform when the
control method of the present invention is used.
The drawing shows that when the conventional control method is
used, the acceleration response time is lengthened due to an
increase of vehicle weight, while when the control method of the
present invention is used, no down-shock occurs in acceleration and
the response time is shortened.
[Effects of the Invention]
The present invention obtains good results indicated below.
(1) When the speed ratio or the deviation between the target value
and the actual value of the primary pulley revolution speed is
small, the speed ratio is controlled accurately on the basis of the
deviation and changes thereof with time. Therefore, the speed ratio
and the engine revolution speed can be changed smoothly; that is,
the speed ratio and the engine revolution speed are prevented from
sudden changes, and the acceleration and deceleration and the fuel
expense are prevented from degradation. When the deviation is
large, the speed ratio is controlled by using the ratio between the
predicting time until the deviation becomes 0 and the predicting
response time necessary for stopping the speed change of the speed
ratio control actuator. Therefore, the time when the deviation
becomes 0 can be synchronized with the time when the speed change
is stopped, the engine revolution speed can be prevented from
overshooting, the acceleration up-shock can be prevented, and the
acceleration and deceleration and the fuel expense are improved.
When the deviation is large, the speed ratio is controlled by the
derivative of acceleration. Therefore, sudden acceleration changes
such as down-shock can be prevented, and the acceleration and
deceleration are improved. When the deviation is small and the
acceleration pedal position variation velocity is small, it is
inhibited to change the speed ratio. Therefore, the sensitivity for
minute changes of the throttle opening for speed ratio variation
can be lowered, wasteful variations of the engine revolution speed
can be prevented, and the fuel expense is lowered.
(2) The engine output is controlled on the basis of the variation
prediction of the vehicle acceleration or the shaft torque of the
drive wheel. Therefore, high speed response to acceleration and
deceleration is compatible with smooth variations, and the
drivability and riding comfort are improved. Particularly, the
variation prediction of the vehicle acceleration or the shaft
torque of the drive wheel is made by using the speed ratio,
transmission input side revolution speed, and engine revolution
speed. Therefore, effects of the speed ratio variation velocity can
be eliminated by engine output control, and high velocity
acceleration and deceleration without a sense of incompatibility
can be realized. The above variation prediction is also made by
using the throttle opening and the vehicle derivative of
acceleration information. Therefore, acceleration down-shock and
up-shock can be removed, and smooth acceleration and deceleration
with rapid response can be realized. Since fuzzy logic is used for
the above prediction and engine control, smooth and rapid
acceleration and deceleration response can be realized.
By using the processing that finite speed transmission and
continuously variable speed transmission are combined at an
optional rate, the driver can find pleasure in finite speed ratio
characteristics, continuously variable speed ratio characteristics,
or optional intermediate speed ratio characteristics. When a
vehicle with a finite speed automatic transmission is changed, the
driver can be slowly become accustomed to continuously variable
speed ratio characteristics without a sense of incompatibility by a
vehicle using the present invention. The driver can find pleasure
in an optional number of finite speeds (3, 4, 5, or more speeds).
Since processing that the speed ratio velocity is corrected by
using the information of a predicting time necessary for reaching
target speed ratio is provided, the driver can easily obtain
transient speed ratio characteristics as desired and the easiness
of maneuverability can be improved.
(3) Even under the condition that the vehicle response
characteristics are changed by changes of the running resistance
such as the number of passengers and gradient and output reduction
of the engine caused by air pressure changes, the best acceleration
response in accordance with the vehicle velocity and the throttle
opening is calculated as a target acceleration response, and the
control parameter is changed on the basis of comparison result
information between the target acceleration response calculated as
described above and the measured acceleration response so that the
acceleration response approaches the target value. Therefore, the
acceleration reduction can be minimized.
Since the speed ratio control parameter is changed by using
comparison result using the acceleration response time and the
index value of down-shock magnitude, a smooth and rapid
acceleration response with a short response time and little
down-shock can be obtained.
Since the target acceleration response using fuzzy logic or the
control parameter change value is calculated, a fine output value
can be obtained for comparison result information between the
vehicle velocity and the throttle opening or between the target
acceleration response and the measured acceleration response.
* * * * *